It is commonly known in the construction industry to create spaces or voids in or under various types of concrete formations. For example, concrete formations below grade such as the structural foundation of a building often require a space or void between the foundation and the ground to accommodate expansion of the soil, thereby preventing damage to the foundation. Thus, it is often desirable to create a void between the structural floor and/or grade beams of a foundation and the underlying soil to accommodate upheaval of the soil. It may also be desirable to create a void between the walls of a foundation and the surrounding soil to accommodate a similar expansion of the soil below grade. In addition, voids can also be utilized above grade between concrete floor slabs to reduce the amount of concrete required and to make the resulting slab lighter.
Another type of concrete formation that sometimes requires a void is a concrete pillar or column. It is often desirable to create a void in a pillar or column to allow room for internal plumbing, electrical conduits or the like within the column. By forming a void in the column, the items within the column are protected and the cost of making the column can be reduced because less concrete is required.
Typically, these voids are created by placing a biodegradable support structure made of corrugated cardboard in the desired location. These support structures are configured to support the building structural components until the poured concrete is capable of holding its own weight. As the concrete dries, and as the cardboard eventually deteriorates, a void is left in the concrete formation. However, such support structures are typically difficult to assemble and often can only be assembled at a factory and transported to a construction site.
It is known to provide a plurality of paperboard panels for assembling at a construction site to form a support structure having an internal reinforcing cell structure. While support structures that may be assembled at the construction site have been known, the prior art structure provides an unsatisfactory compressive strength. Of the many features which in combination provide the overall compressive strength, the prior art provides triangular shaped peaks which serve as interior supports for the support structure side walls. Such triangular peaks offer low compressive strength and thus adversely effect the quantity of concrete that may be supported by the support structures.
Therefore, it remains desirable to provide an inherently strong support structure having excellent compressive strength and that can be either delivered factory assembled to the construction site, or delivered in a "knocked-down" configuration for easy assembly and installation on site.